Amavisd-new disclaimer and DKIM signing

I am having an issue with getting Disclaimer and DKIM signing with my amavis config. I am adding the html signature ok and the message is being signed but it is failing verification when it gets to the recipient. I can run amavisd-new testkeys and it passes locally, the DNS records are the same on my local and external DNS server. It fails the SM and LL Sig tests on unlocktheinbox, with bad signature.

Any help on this is greatly appreciated, and any further info just ask and I will post relevant configs etc.

I have tracked this down further and found out what the exact issue is and its not related to the DKIM signing.

If i changed the disclaimer to txt only the messages get signed, the problem seems to be with amavis changing the html when its inserting into the email. I have noticed that all spaces in the original html are replaced by '20' in the sent mail so this seems to be causing the body has failure.

How do i set the content-type and or content-transfer-encoding for amavis/altermime to stop it changing my html?